(1) Field of the Invention
The present invention relates to a photocurable primer composition capable of being quickly cured by light irradiation, and showing good properties in workability, adhesion to a substrate, abrasion properties, etc., and to a coating method by use of the photocurable primer composition. The photocurable primer composition of the present invention may be used in coating an automobile body, a railway vehicle, an industrial equipment, woodworking, etc., and the coating method by use thereof makes it possible to provide good finish in a very short period of time, and is particularly useful as an automobile repair coating method.
(2) Description of the Background Art
A repair coating of an automobile body, etc. in the art mainly consists of the following successive steps of {circle around (1)} a step of thick applying a body filler to a damaged area, followed by drying and abrading a body filler-applied surface, {circle around (2)} a step of coating thereonto a primer surfacer in order to achieve topcoating finish properties, followed by drying and smoothly abrading the coating surface, and {circle around (3)} a step of coating a topcoating, resulting in that the above coating, drying and abrading steps take a very long period of time. Recently, for the purpose of shortening a period of time taken for the repair coating as a whole, a repair coating by use of a photocurable putty composition has been proposed As examples of the above photocurable putty composition, a photocurable coating composition containing a polymerizable unsaturated group-containing resin and a photopolymerization initiator is disclosed in Japanese Patent Application Laid-Open Nos. 117588/79, 137089/97 (U.S. Pat. No. 5,852,067), 100306/97, etc. However, use of the above coating composition as a repair coating surfacer resulted problems of showing unsatisfactory coating film performances in abrasion properties, hardness, adhesion properties, water resistance, etc.